[85MUSTANGGT]

This was forwarded to me by 85MustangGT to post for him so give him all the credit for this one.

5-Lug / Disc Brake Swap

Introduction

This purpose of this thread is to discuss the possible ways to perform the 5-lug and/or disc brake swap on the '79-93 Fox Mustang. I would like for other members that have done this swap to describe where you found your information, list the parts you used, any problems you might have had, and your opinion of how the new parts worked when completed (in a similar fashion to what I have done) for others to follow as a reference. There are many ways to do this conversion, whether it is simply a 4-lug disc brake swap, SVO swap, SSBC kit, SN95 swap, etc. please describe it in this thread.

Anyone that can perform a brake job, bleed brakes, and replace shocks and struts can do this swap easily. If you have all the necessary parts, I would say this swap could be done in a weekend - providing you can find an alignment shop open. Something to remember is that the '79-86 brake systems are slightly different from the '87-93 systems and require different parts, such as the 3-2 port conversion described in the link below. Hopefully this thread will be helpful for those looking to have 5-lugs and/or all-wheel disc brakes.


My Swap

This website, 79-93 5 Lug Ford Fox Body Mustang Conversions, is where I found most of my information during my conversion. It covers everything from choosing spindles and axles to calipers and master cylinders. I found it very good. I also studied the installation instructions for the Ford Racing M-2300-K Cobra Brake Kit and can be found on the Ford Racing website in .pdf format. It made a good checklist and provided torque specs. The following is my experience of the 5-Lug/Cobra brake swap on my 1985 Mustang GT.

The Front

Parts:
’95 V6 Mustang Spindles from Salvage
MOOG Ball-Joints for ’94-95 Mustang from Auto Parts Store
Cobra Calipers from Ford Racing (M-2320-AF)
Wagner Rotors for ’94-04 Cobra from Auto Parts Store
Stainless-Braided Hoses made by me from Aeroquip components
Banjo Bolts from Ford Racing (M-2321-A)
Caster/Camber Plates from Maximum Motorsports

The front was pretty straight-forward. My ball-joints needed to be replaced so I replaced them with the SN95 pieces. The SN95 ball-joints are slightly different from the ’79-93 ball-joints in that the threads are shorter, however, it’s not necessary to replace ball-joints as a spacer or washers can be used under the spindle nut. The spacer or washers need to be about 3/8” thick. The only real problem I had was the ’79-86 spindles are 1” thick at the strut connection, whereas the post-‘87 spindle is ¾” thick. Since my car is on the opposite side of this change from the new spindles, I had to make shims to remedy this until I can upgrade my struts with post-’87 style struts with the narrower saddle. The caster/camber plates are a necessity in order to set the proper camber. I also had to adjust the tie-rod ends out approximately ½”. I wasn't sure what brake hoses would have the right fitting to fit my car so I decided to custom make my own. All brake hoses I could find were listed to fit the ’87-93 Mustangs and was unsure if they would work on my car. I had to re-flare the hard lines on the front with a 3/8” tube nut (the stock ones were 7/16") to work with the Aeroquip fittings, not a big deal for me. For the banjo bolts I chose to use the Ford Racing kits since I knew the threads would be the right size. You’ll need two of these banjo bolt sets, one each for the front and rear. While installing the stainless hoses, I noticed they were really good about scratching off paint. I went to the hardware store and bought some 5/16" ID clear vinyl tubing, installing it over the areas that I thought would rub holding it on with small zip-ties. Don't forget that an alignment is necessary as the toe and camber settings will be off. Just get the toe and camber set as close as you can, then drive straight to the alignment shop when you're done. You can stop at McDonald’s afterwards.

The Rear

Parts:
Complete 8.8” Rear Axle Assembly out of a ’98 Mustang GT from Salvage
Cobra Rear Brake Bracket Kit from Ford Racing (M-2300-M)
Stock ’98 GT Brake Calipers from Salvage
Parking Brake Cables from Ford Racing (M-2809-A)
Stainless-Braided Hoses made by me from Aeroquip components
Banjo Bolts from Ford Racing (M-2321-A)

Since I needed to replace my 7.5” rear axle with the 8.8” counterpart, I just bought a complete axle assembly from a local salvage. The 8.8” axle was completely rebuilt during this time and the new brake brackets that bolt to the end of the axle tubes were installed. Rotors are included in the bracket kit. The calipers I used came on the salvage axle. I cleaned them up, painted them to match the front calipers, and installed new pads. I had to remove some material from the inside of the caliper bracket to clear the thicker cobra rotor, removing approximately 1/32" on each side of the rotor using a die grinder and cut-off wheel. I only needed the two rear parking brake cables described in the M-2300-K instructions as my parking brake does not use a center cable or have the self-adjusting mechanism like the ’87-93 models that needs to be modified per the Ford Racing instructions. Again, I made the brake hoses for the rear and used the Ford Racing banjo bolts as well.

Master Cylinder & Proportioning Valve

Parts:
1985 Lincoln Towncar Master Cylinder from Auto Parts Store
Proportioning Valve Plug from Ford Racing (M-2450-A)
Adjustable Proportioning Valve from Ford Racing (M-2328-C)

I followed what I read on the website mentioned above to choose a master cylinder. The Lincoln master cylinder is the same style as my original (one-piece, cast aluminum), but with the larger 1” bore to work properly with the disc brakes. I believe stock bore is approximately 13/16”. The Lincoln master cylinder also has different sized threads requiring me to re-flare one of the steel lines that runs to the factory proportioning valve. I was able to swap the factory rear line to be the new front line and the original front line got re-flared with a larger size tube nut (a 9/16" if I remember correctly) to be the new rear line. The factory proportioning valve got gutted per the Ford Racing instructions with the new plug and the adjustable proportioning valve installed in the union by the passenger side hood hinge. I opted not to worry about finding a different brake booster during the install and decided after driving the car for a while that the stock booster was sufficient and I wouldn't change it.

Conclusion

I have been pleased with the results of this conversion. I have a better brake system than before and the car tracks and steers well. Not only that, the car looks so much better with the ’03 Cobra wheels and 275/40 series tires I chose to use. I did this conversion about a year ago so hopefully I didn’t forget anything too important.

[85MUSTANGGT]

I was beginning to wonder what happened to this.

[EagleAutosports]

Sorry about taking so long to get it here, but it's here now.

[swpdcop]

good info, thanks for posting. is the master cyld. the same look and brake light warning wires? or is this the same as the 85 model? not the newer stle like the 89 had with the plastic top?

[85MUSTANGGT]

My master cylinder is the old style (see pic). The '79-86's use a slightly different set-up than the '87-93 models. You can click the link to the website that is in the first post then on that page, click the MC & PV link on the left. It lists the options of master cylinders and explains what set-ups to use them with.

[swpdcop]

Yeah that`s the one that came with the kit that I just got. Waiting for better weather to install, I have a small garage too do the conversion in. I have to pull the axles out too do the job. To cold for that and don`t want not be able to finish in one day. Then would have to leave it out side in pieces. Winter sucks!

[EagleAutosports]

Think this'll be stuck to the top now.

[79stangghia]

I remember reading some place that the rotors from an early 90s Ranger will fit the stock spindals. For my 79 I stayed with the 4 bolt and I used rear disk breaks off of a turbo coup. It all bolted right up and the break hose need adaptors. I used an SVO MC. I think for the rear breaks SVO or SN 95 would be the best way to go because I think they are slightly bigger than the coup's, plus they are 5 lug.

[shakerhood]

Luke's Website is a pretty good source for instructions too.

Mustangmotorsport - Mustangs and a whole lot more!

[throwback_king]

So how much did everything cost?

[85MUSTANGGT]

For me, appoximately $2600 with wheels, tires, and the axle swap.

[svtjoe]

why dident you just go to the junk yard and got a mark VII rear end with disk brakes and all

[85MUSTANGGT]

I could have I guess, just not what I wanted. I could have spend a lot less by searching for and buying used parts also, I would rather have new parts though. Personal preference.

[bolivartech]

Is what 79stangghia said true about the rotors? Would it be possible to get the rear conversion kit for a 79 and rotors from another source. That seems like it'd be the least amount of work to slide on some 5 lug tires.

[85MUSTANGGT]

What year and model is your car? Pull up the link from the first post. It tells what 5-lug rotors you can use with the stock spindles. Rotors from a Ranger will work on some models, rotors from a Lincoln will work on others.